Gas turbine systems include a rotor unit mounted to rotate inside a stationary external housing and generally have a gearbox that is mounted to the external housing. The gearbox is generally positioned adjacent the turbine engine and coupled in a manner to use power from the turbine engine to drive the engine's accessories such as electrical generators, fluid pumps, and heat exchangers for cooling oil or heating fuel. At least two supports, longitudinally spaced apart, are used to bear various loads of the engine and its gearbox, for example, the turbine engine is mounted at its aft end and mounts to the gearbox at the forward end. The loads typically include vertical loads such as engine weight, axial loads due to engine generated thrust, and lateral and roll loads depending on the engine's application.
Aft engine mounts typically are provided with a spring or other biasing member to provide a spring force to the engine in the vertical direction. However, spring loaded aft mounts have proved to behave inconsistently, with difficulty in highly variable spring forces (up to 1000 pounds), in provision of nonplanar surfaces, and in maintaining consistent leveling. Because of defective aft mounts, the engine cantilevers and causes gearbox misalignment with the engine. As a result, one or more gears within the gearbox experiences additional loading to cause excessive wear on the teeth. Hence, the gearboxes of engines with spring loaded aft mounts can be susceptible to failure due to the engine not being fully supported and/or excessive variability in engine position. Further, setup of spring loaded aft mounts by a technician can be highly variable.
One device and method for mounting is described in U.S. Pat. No. 8,028,967 To Busekros et al. In particular, this patent discloses a gas turbine engine mounted on a base frame via a support. The support provides a support face in operational engagement with the base frame by way of a plurality of support plate elements. Merely changing the arrangement of only the support plates makes it possible to make later adjustments to the mounting of the a gas turbine system in order to minimize vibration and bear the weight of the engine. A lifting device is provided to briefly raise the gas turbine engine such that the support plates' arrangement can be modified.